The MIT Nuclear Products Generator for development of ICF diagnostics at Omega / Omega EP and the NIF

Transcription

1 Introduction

2 The MIT Nuclear Products Generator for development of ICF diagnostics at Omega / Omega EP and the NIF SBDs d + or 3 He +(2+) D or 3 He target Present MIT Graduate Students and the MIT Nuclear Products Generator Omega Laser User s Group 1 st Annual Workshop Wednesday, April 29 th, 2009

3 Internal and external users and collaborators Present Graduate students: N. Sinenian D.T. Casey M. Manuel H.G. Rinderknecht M.J. Rosenberg Scientists J. A. Frenje C.K. Li F.H. Seguin R. D. Petrasso External Users / Collaborators V. Tang (LLNL) M. Akselrod (Landauer Inc.) J. Sykora (Oklahoma State University) i Past Graduate students: J. DeCiantis (KAPL) J.R. Rygg (LLNL) S. Kurebayashi (Goldman Sachs) S. Volkmer (Harvard) C. Chen (LLNL) Past Undergraduate students: D. B. Denis (Westinghouse) M. Canavan (RPI / PPPL) R. Leiter S. McDuffee (Columbia) J. Perez (senior) S. Virk (senior) J. Jacox (senior)

4 Summary The MIT acceleratoriscapableof capable of producing fusion products and ion beams relevant for Inertial Confinement Fusion (ICF) and Magnetic Confinement Fusion (MCF) applications. The accelerator has been very instrumental in designing, optimizing, characterizing several types of fusion plasma diagnostics**. It is currently used to support the development and calibration of new and existing diagnostics for use at OMEGA, OMEGA EP and the NIF. ** F.H. Séguin et al., Rev. Sci Instrum 74, 975 (2003). V. Tang et al., Rev. Sci Instrum 77, (2006) S. McDuffee et al., Rev. Sci Instrum 79, (2008)

5 The MIT nuclear products generator is capable of producing fusion products and beam ions relevant for ICF/MCF diagnostics development Ion beam

6 Fusion products produced by the accelerator

7 The accelerator is capable of producing several fusion products and beam ions Primary products (kinematics not included): D + D T (1.01 MeV) + p (3.02 MeV) D + D n (2.45 MeV) + 3 He (0.82 MeV) D + 3 He α (3.6 MeV) + p (14.7 MeV) Secondary products: 3 He (<0.82 MeV) + D a ( MeV) + p ( MeV) Beam ions: D + (<150 kev) 3 He + (<150 kev) 3 He 2+ (<300 kev)

8 Fusion products can be produced by running a D + beam on 3 He 120 kev D + beam on 3 He Fusion product rates up to ~10 7 /s are readily achieved

9 Radioactive sources and kinematic calculations are used to characterize the energy of the fusion products # / bin b [au] Ra source (α-source) for instrument calibration MeV # / bin kev D + beam on 3 He DD-t (1.0 MeV) DD-p (3.0 MeV) D 3 He-p (14.7 MeV) Channel MeV

10 Kinematic effects and ranging filters are exploited to provide fusionproductswith a large range of energies SBDs New proton spectrometers d + or 3 He 2+ #/ Bin D 3 He-p µm Al MeV Θ lab Θ 700 lab DD-p D or 3 He target # / Bin MeV 6 µm Al

11 Primary Objectives

12 The objective with the accelerator is to design and characterize instruments for diagnosingicf plasmas at OMEGA, OMEGA EP EP ~240 feet Capsule diameter ~1 mm A direct-drive implosion 60 laser beams delivering 30 kj on capsule in ~1 ns Direct or indirect drive

13 and the National IgnitionFacility (NIF) at LLNL ~600 feet Person Inside the NIF target chamber 192 Laser Beams delivering 1.8 MJ on capsule Indirect drive or direct drive First credible ignition experiments ~2010 Cryogenic Hohlraum (length ~ 9 mm)

14 Projects on Accelerator

15 a) Calibration and optimization of an X ray/emp immune, CR 39 based detector for the measurement of neutron yields Erbium Target Neutron Detector 1mm Ta + 100um CH + CR 39 Silicon Barrier Detector The fusion products generator is being used to characterize and optimize the efficiency of the neutron detector for sensitive measurements of neutron yield at OMEGA/OMEGA EP and the NIF um 50 um 0um recoil proton tracks X position, cm Experimental Setup Scanned image of CR 39 Number of tracks vs. position [1] J.A. Frenje et al., Rev. Sci. Instrum. 73 (2002). [2] The Optimization of an EMP/X Ray Immune CR 39 based detector for Sensitive Measurements of Neutron Yields at Omega & the NIF OLUG Workshop, April 29 th May 1 st, 2009

16 b) Calibration of the compact proton spectrometers** currently used on OMEGA TP CPS Compact proton spectrometers These spectrometers are used extensively at OMEGA for measurements of either primary or secondary protons, from which rr and rr asymmetries can be determined for a large range of capsule implosions ** F.H. Séguin et al., Rev. Sci Instrum 74, 975 (2003).

17 The old spectrometers were recalibrated on the accelerator to account for any changes from extensive use at OMEGA Tracks / bi in Incident D 3 He-p 150 μm Ta t Al wedge CR-39 ( 10 3 ) Peak 1 Peak Trac cks / bin ( 103 ) Peak 2 Peak 1 Θ lab = Energy [MeV] Peak: 1 2 e Measured (MeV): Anticipated (MeV): Ref. line X [cm] No significant changes have occurred during severalyears of operationat OMEGA

18 The new proton spectrometers were absolutely calibrated on the accelerator using D 3 He protons Incident D 3 He-p Broad-band spectr. CR μm Al D3He-p lines Reference data CR μm Al Broad-band spectr. CR μm Al Narrow-band spectr. CR μmal Fiducials for alignment and energy calibration X [cm]

19 Projects (continued)

20 c) Optimization of the Coincidence Counting Technique (CCT) for the Magnetic Recoil Spectrometer (MRS)** Implosion CH-foil or CD-foil 10 cm Back side 215 cm Front side Magnet housing OMEGA 6-30 MeV (p) 3-15 MeV (d) CR-39 Detector housing Top view This spectrometer measures the absolute neutron spectrum (6 30 MeV) from which rr, T i and Y n can be determined for a large range of implosions. ** J.A. Frenje et al., Rev. Sci. Instrum. 72, 854 (2001). J.A. Frenje et al., submitted to Rev. Sci. Instrum. (2008).

21 The CCT for the MRS at OMEGA was developed and optimized using the accelerator CR-39 R c Aligned scans Misaligned scans Proton signal Neutron Background** R l Δy [μm] Signal Random coincidences R c ~ 50 μm Coun nts / Pixel Intrinsic track Front side Back side Δx = x front -x back [μm] By applying the CCT, S/B is enhanced orders of magnitude* 0 * D.T. Casey et al., to be submitted to Rev. Sci. Instrum. (2008). ** J.A. Frenje et al., Rev. Sci. Instrum. 72, 2597 (2002).

22 d) Characterization of new sensitive CR 39 planned to be used in proton radiography applications at OMEGA CR-39 D 3 He-protons Fluence Images Proton backlighter Imploding conein-shell capsule CR-39 t = 0 ns t = 1.5 ns Foil D 3 He-protons The energy of D 3 He protons from the back lighter must be ranged down to the energy window in which the CR 39 detection efficiency is 100% J.R. Rygg et al., Science 319, 1223 (2008).

23 DD p and D 3 He p were used on the accelerator to characterize the response of new sensitive CR 39 Dia ameter [μm m] Standard (TASL) Chiyodo ATP 13.4 MeV protons (Chiyodo) MeV Noise floor ** The tracks are made visible through etching in 6M NaOH. In this case, the CR 39 was etched for 6 hours.

24 Projects (continued)

25 e) Characterization of Fluorescent Nuclear Track Detector (FNTD) response to fusion products Aluminum Oxide (Al 2 O 3 : C, Mg) CNPA FNTD advantages relative to CR 39: Superior spatial resolution (< 1 mm) Wider range of LET sensitivity (< 1 kev/mm) Au Reusable foil after annealing

26 The FNTD response to D 3 He p, DD p and D 3 He alpha particles were characterized usingthe accelerator CNPA d + Au foil Experiments were performed in collaboration with Landauer Inc. and Oklahoma State University

27 f) Calibration of the Compact Neutral Particle Analyzer (CNPA) for the Alcator C mod Tokamak Si diode detectors in pulse height mode are used to measure energetic hydrogen minority ions with energies between 40 and 350 kev stemming from ion cyclotron radio frequency heated D(H) plasmas. ** V. Tang et al., Rev. Sci. Instrum. 77, (2006).

28 RBS deuterons ( kev) produced by the accelerator were to used to calibrate the CNPA** 100 CNPA d + Counts / bin kev RBS deuterons Voltage [V] Experiments were performed in collaboration with the Alcator C mod group Volta age [V] DNB X-rays RBS deuterons 0 Au foil kev